Final answer:
The nurse observes for lifts and heaves in the precordium, which is the area covering the heart and lower thorax important for assessing cardiac activity.
Step-by-step explanation:
The area of the body where a nurse observes for lifts and heaves is the precordium. The precordium is the region on the anterior surface of the body covering the heart and the lower part of the thorax, which includes the second to the sixth rib spaces and the sternum. During a physical examination, lifts and heaves can indicate underlying cardiac conditions, such as hypertrophy or increased ventricular activity, necessitating further evaluation.